1. Field of the Invention
The invention relates to a method of manufacturing integrated circuits by which a number of similar circuits are manufactured jointly on a semiconductor slice and then separated from one another by cutting, each circuit being provided at the rim with several connection pads, some of which are used exclusively for testing the circuit before it is separated from the adjoining circuits.
The invention also relates to an integrated circuit which is manufactured on a semiconductor slice jointly with a number of similar circuits and then separated from these by cutting, each circuit being provided at the rim with several connection pads, some of which are used exclusively for testing the circuit before it is separated from the adjoining circuits.
2. Description of the Related Art
The manufacture of a large number of integrated circuits together on one semiconductor slice by means of diffusion and etching processes, especially by the use of photolithographic means, is generally known. After these manufacturing steps have all been completed, each single circuit on the semiconductor slice is tested for correct operation in the following way: test probes mounted to a device are put on the connection pads of a circuit each time, and an operating voltage or test signals are supplied and output signals are taken up through these probes. Incorrectly functioning circuits are marked after each test cycle, so that they no longer take part in the subsequent manufacturing steps, especially building-in into a housing and the connection of the connection pads to external connections through wires.
Digital circuits in particular can first be tested only by way of the connections used in normal operation, but such a test is very laborious, for example in the case of highly complex circuits or also circuits with very few external connections, such as, for example, circuits used for contactless chip cards. The test can be substantially simplified when additional connections are applied for testing only, through which the additional test signals are applied to the circuit or output signals are conducted to the exterior, these connections not being used for normal operation. Since the total size of connection pads, however, is relatively great in relation to the elements of the circuit proper, which is also true for the connection pads for testing, a substantial portion of the semiconductor slice is used for such connection pads in this way, so that fewer circuits can be realized on a semiconductor slice of a given size and the manufacturing cost of a single circuit is made higher.